9V size Nickel-Metal Hydride (Ni-MH) 9 volts, 180mAh charges upto a 1000 times. 1 Battery in a Pack 9V Nickel-Metal Hydride (Ni-MH) 9 volts batteries, 180mAh charges upto a 1000 times. Commonly used in small battery-powered devices, Far out performs NICAD batteries.. NiMH batteries do not use heavy metals that may have toxic effects. In addition, they can store up to 50% more power than NiCad batteries and do not suffer from memory effects.